Process of concentrating solutions.



No. 723,152. PATENTED MAR. 17, 1903.

- A. GERBER.

PROCESS OF CONGENTRATING SOLUTIONS.

APPLICATION FILED JAN. 30, 1906. no MODEL.

3 4 4.: min/0;. i dim Am UNITED STATES AUGUSTMGURBER, or WURZBURG, GERMANY.

PROCESS OF CONCENTRATING SOLUTIONS.

SPECIFICATION forming part of Letters Patent No. 723,152, dated March 17, 1903.

Application filed January 30, 1900- $erial No. 3,340. (No specimens-l which Ihaveapplied forapatentin Germany, dated July 15, 1899; in Denmark, dated Angust 19, 1899; in England, dated August 24, l899,andin France,dated September11,1899,) of which the following is a specification.

The product hitherto known to the trade as condensed milk has the disadvantage of an unnatural taste, as well as a peculiar odor,

both of which are due to the methods of concentrating the same by evaporation as usually employed. Ordinarily the milk is subjected to prolonged boiling, and chemical changes are brought about by the heat which impair the nutritive value of the milk constituentsandimparta peculiar odor and taste, as of cooked milk. Furthermore, prolonged heating of the milk at comparatively high temperatures ruptures the fat-globules and renders the product not only more susceptible to deteriorating chemical changes, but imparts to the same a disagreeable unctuous or greasy taste. Also under such methods of preparation it is found necessary. to add a very considerable portion: of sugar. Such highly-sweetened condition not only unfits the product for many culinary purposes, but also renders the same highly injurious for use as a diet for infants.

By my improved method of concentrating or'oondensing milk I entirely dispense with the use of heat and produce an article that is odorless, has an unimpaired natural taste, will keep admirably, and in which the fatglobules'are preserved intact, the product being the natural milk minus a large proportion of its water. a

In order to avoid the objectionable defects common to condensed milk prepared by the ordinary well-known methods and to obtain a product having the desirableattributes enumeratedJproceed to carry out myinvention in the manner following,to wit: The fresh milk is first separated from the cream in the ordinary way by centrifugal action, the cream being reserved and added to the product later on. The skimmed milk is then placed in a suitable centrifugal machine, preferably having a central coil or chamber containinga refrigerating medium, such as ammonia, brine, or the like. The centrifugal machine is .then started, and as the freezing action proceeds the watery constituent of the milk is congealed into ice-crystals, which crystals are, by reason of their less specific gravity, displaced by the heavier solids and caused to accumulate about and adhere to the central coil or refrigerating-chamber, the more concentrated milk solution, deprived of a large portion of its water, finding its way to the outer periphery of the drum, whence it may be drawn 0K in any well'known manner. The product may be withdrawn at an intermediate stage of concentration and subjected to further similar treatment or the exit-valves may be so adjusted as to accomplish the desired high degree of concentration mono and the same continuous treatment .by subjecting the contents of the drum to the action of refrigeration and centrifugal separation during a sufiiciently-extended space of time. The mass of ice collected about the central refrigerating coil or chamber will in practice contain a certain amount of solid matter locked up between the crystals, varying with the nature of the liquid to be concentrated and the degree of centrifugal force applied. If it be desired to carry to its full extent the concentration of the matter undergoing treatment, the central mass of ice may be melted by the application of heat, as by the admission of steam to the refrigerating-coils, thus freeing any solid particles that may be inclosed within the ice, and then by repeated freezing under the influence of continued centrifugal force accomplish a further concentration. Such alternate freezing, thawing, and freezing may be continued untilthe solid matter is practically all separated from its watery constituent, when the concentra te may be withdrawn. After the withdrawal of the concentrated product the congealed water inthe form of ice may be removed by the application of steam or other convenient form of heat, when the drum will be ready for the condensing of other milk. After the withdrawal of the condensed milk from the apadded thereto and the product is ready for use. The condensed milk thus obtained differs from the article as ordinarily produced by evaporation in the particulars hereinbefore stated and may be diluted by the addition of water'to the original volume and will then have. the taste of fresh milk and will not exhibit the disagreeable odor or the unnatural sweetened taste and flavor of the ordinary condensed milk.

WhileI have herein described my process as applied to the concentration or condensing of milk as a typical example of its application, I desire it to be distinctly understood that I do not limit myself to the treatment of milk, as my process'is obviously valuable in the concentration of a great variety of liquids and solutions, and particularly those containing albumen and other substances which, like milk, are deleteriously aifected byv the heat in the 'ordin'arysprocess of concentrating by evaporation.

While my process is entirely separate and distinct from any particular form of apparatus adapted to the carying out of the same, yet for the purpose of illustration I have in the annexed drawings shown a preferr'ed form of centrifugal machine in which is supported centrally a coil or a chamber 6, adapted'to contain the refrigerating solution and which may or may not rotate with the drum, the said chamber or coil being provided with an inlet fand an outlet 9, as shown. As hereinbefore fully set out, when the refrigerating medium is admitted to the central coil or a stance, through the channels it, leading to an outlet 2' in'the axle b of the centrifugal machine-while the ice remaining may be melted by steam injected into said coils or chambers or applied to the exterior thereof.

In carrying out my process it will be understood that I may use centrifugal machines of various constructions, and I may subject the solution to the freezing medium necessary for the freezing outof the water, as-well as to' the heating agent necessary for. the thawing of the ice, in different ways. The freezing medium, moreover, may consist of any wellknown cooling liquid, gas, or the like, and

Letters Patent, is

may in some instances be applied directly to the solution.

Having thus fully described myinvention, what I claim as new, and desire to secure by 1. The process of treating solutions which consists in freezing out the watery constituents and simultaneously by centrifugal action effecting separation therefrom of the portion containing solids in concentrated form.

2. The process of efiecting a concentration of liquids, which consists in subjecting the same simultaneously to a freezing temperature and to centrifugal action thus elfecting a removal of the concentrate from the dilute portion.

3. The process of effecting a concentration of liquids, which consists in'subjecting the same simultaneously to centrifugal action and 'to a freezing temperature applied GED1- trally of the mass. I

4. The process of condensing milk, which consists in congealing the watery portion by refrigeration and at the same time by centrifugal'action efiecting a separation there, from of the portion containing solids.

5. The process of condensing milk,'which consists in subjecting the same to centrifugal action and simultaneously submitting the central portion'of the same to the influence of a freezing medium.

6. The process of condensing liquid solutions, which consists in alternately freezing and thawing the same while under the influence of centrifugal action.

7. The process of condensing milk, which consists in subjecting/the same simultaneously to a freezing temperature and to centrifugal action, then thawing the frozen portion and again freezing while under centrifnioo gal action. I

8. The process of condensing milk, which consists in removing therefrom the cream, then freezing out the watery constituent and simultaneously by centrifugal action elfectx05 ing a separation therefrom of the concentrate, and then adding to the concentrate the cream previously removed.

9. The process of producing condensed milk, which consists in' removing therefrom no the cream, alternately freezing and thawing the milkfwhile under the influence of continued centrifugal action, and then adding .the crea'mto the condensed product.

In witness'whereof I have hereunto set my :1 hand in' presence of two witnesses,

' AUGUST GURBER. Witnesses:

' HANS HUNGER, OSCAR BOOK. 

